The phones will cost $649 for a 16GB iPhone 4S and $549 for an 8GB iPhone 4.

The no-contract service plans starts at $30 a month, including a $5 discount, for 300 minutes of voice and unlimited texting and data. A $50 per month plan, with the $5 discount, offers unlimited voice, texting and data.

There are no fees for activation or roaming, Virgin Mobile said in a statement.

The $5 discount applies when customers agree to have monthly payments made automatically from a credit, debit or other account.

The offer comes as Virgin Mobile, a unit of Sprint, celebrates 10 years in business, said Sir Richard Branson, the founder of Virgin Group.

The iPhone for Virgin Mobile will be available online and at Radio Shack, Best Buy and other local retailers.

Cricket, another Sprint partner, recently announced it will sell prepaid iPhone services as well.

Cricket will start its prepaid iPhone sales on June 22, a week earlier than Virgin Mobile.

The Cricket phones are priced lower than Virgin Mobile's, but the monthly plans are more expensive.

The Cricket iPhones are priced at $500 for the 16 GB iPhone 4S and $400 for the iPhone 4 8 GB. The Cricket pre-paid service plan will provide unlimited talk, text and data for $55 a month.